People object to the word donor, because there is compensation involved.

However, an egg donor is being paid for her time and effort, not her eggs. The donor would have been paid the same no matter how many eggs were retrieved (compensation is not based on results).

Organ selling is not legal, but the analogy of a donated kidney does not apply to egg donation. You only have two kidneys. A donor has many eggs, and those retrieved for donation would have been released and discarded by her body in a normal cycle (she is not depleting her ovarian reserve). In this aspect, it is more like plasma donation.